Wind-induced responses and dynamics characteristics of an asymmetrical base-isolated building observed during typhoons (original) (raw)

Responses of an asymmetrical base-isolated building during the passage of Typhoon Roke 2011, Typhoon Guchol 2012 and a bomb cyclone strong-wind event on April 3, 2012 were investigated in this paper. Windinduced accelerations of the building were recorded by dense array permanent monitoring system and analyzed in detailed by spectra analysis, time-frequency wavelet analysis and system identification. Results of analysis revealed that wind-induced responses of the buildings were dominated by the first mode which is the fundamental flexural mode coupled with torsion of the upper stories. Building responses demonstrated nonlinear characteristics of natural frequencies, damping ratio and mode-shapes. Natural frequencies of fundamental modes decreased with the increase of acceleration amplitude, with the maximum reduction of 8-10% of natural frequencies observed during the peak wind speed. Damping estimates of the fundamental modes increased with the increase of accelerations, while characteristics of mode-shapes were also found to be dependent on the wind speed. Further analysis revealed that non-linear characteristics of building responses are related to isolator deformations caused by wind-induced static force.